Halogen liberating/color former light sensitive systems having increased speed

ABSTRACT

Nonsilver, organic, dry-processed, violet and blue radiation sensitive free-radical films for recording and duplicating applications. The latent image may be optically developed in a period of 2 to 3 seconds by uniform exposure to red and near infrared radiation after an initial exposure in the region of 1 to 10 mj./cm.2 in the violet or blue regions of the spectrum. The image color is close to neutral. Fixing is accomplished by heating the film to a temperature of 150* C. for 60 seconds.

United States Patent nu 3,624,228

[72] Inventor Richard A. Fotland 3,042,5l6 7/l962 Waine r 96/48 yn r ch10 3,351,467 [1/1967 Sprague et al. 96/90 [21] pp 831.701 3,5 |0,300 5/1970 Fotland etaL... 96/48 x Filed June 1969 3,140,948 7/1964 Stewart et al 96/90 [45] Patented Nov. 30, I971 T [73] Assignee Horizons Incorporated, aDivision of 'f Nolimana' m H R Inc M AEEEQZELEZQMHM :B EhiE-IQLQL 0 mm para Attorney-Lawrence l. Field [54] HALOGEN LIBERATING/COLOR FORMER LIGHT SENSITIVE SYSTEMS HAVING INCREASED SPEED 9 Claims, No Drawings [52] U.S.Cl 96/48, ABSTRACT; ilver, organic, dry-processed, violet and 96/90 blue radiation sensitive free-radical films for recording and [51] IIILCI G03c 5/24, duplicating applications The item image may be Optically 1/72 developed in a period of 2 to 3 seconds by uniform exposure [50] Field of Search 96/90, 48 to red and near infrared radiation after an initia] exposure in 2 [56] Retemnces Cited the region of I to l0 m Jcm. In the violet or blue regions of the spectrum. The image color is close to neutral. Fixing is ac- UNITED STATES PATENTS complished by heating the film to a temperature of 150 C. for 3,042,515 7/ I962 Wainer 96/48 60 seconds.

HALOGEN LIBERATlNG/COLOR FORMER LIGHT SENSITIVE SYSTEMS HAVING INCREASED SPEED The invention herein described was made in the course of, or under a contract with the United States Air Force Systems Engineering Group, Wright-Patterson Air Force Base.

This invention relates to improvements in nonsilver free radical photosensitive films of the type described in U.S. Pat. No. 3,042,5 l5 issued to Eugene Wainer on July 3, 1962, and to other later patents describing modifications of the compositions originally described in U.S. Pat. No. 3,042,515.

In general, these already known compositions consist essentially of the following:

1. at least one organic halogen compound in which at least three halogen atoms are attached to a single carbon atom, or an organic sulfur compound of the types described in U.S. Pat. No. 3,285,744, for example; and

2. at least one color forming compound such as a dior triphenyl methane compound which forms a colored product when it reacts with the products resulting from the exposure of the activator 1) described above to a dose of radiation. The color forming compound may be an arylamine as described in U.S. Pat. No. 3,042,5 l5, instead of the leuco compounds described in U.S. Pat. No. 3,285,744 or other color forming compounds described in the patents noted in column 1 of U.S. Pat. No. 3,377,167 issued Apr. 9, 1968.

Already known compositions include additional constituents, such as triaryl compounds of Sb, As, Bi and P described in U.S. Pat. No. 3,377,167, and phenols described in U.S. Pat. No. 3,351,467, both of which improve the prior art photosensitive compositions.

The present invention is directed to the incorporation of various aminostilbene compounds into such photosensitive compositions and another aspect of the invention is directed to the incorporation of primary aliphatic or alicyclic amines, in critical amounts, into the compositions of this invention.

While not wishing to be bound by any specific theory, it is believed that the stilbene compound forms a colored dye salt with the organic halogen compound and the diphenylmethane color former when photolytically activated and that this additive increases the film speed by diminishing the tendency for fogging.

The primary amine appears to titrate out any dye salt impurities and to thereby increase film speed. If an excess of the primary amine over that required to titrate out any dye salt impurities is added to the formulation, the contrast or gamma of imagery formed is increased. This effect is believed due to the fact that the primary amine reacts with colored salts initially formed in the exposure to an extent depending upon the concentration of amine. This, in essence, eliminates salt formed in the low exposure regions, thus providing an induction effect on the film response to light and hence a steepening of the H and D curve.

The following examples are intended to further illustrate the invention and are not intended to be taken as limiting the invention in any way.

EXAMPLE 1, PRIOR ART A duplicating film was prepared by casting the following formulation onto a clear support with a wet thickness of mils and permitting the solvent to evaporate as described in the Journal of Photographic Science and Engineering, 5, 98 I961). The film was dried in an oven for 2 minutes at 80 C. in order to remove residual solvent.

400 mg. 4.4'-vinylidene-bis-( N,N-dimcthylanilinc) I00 mg. 2.6-di-tcrt-hutyl-p cresol mg. lriphcnylstihine 50 mg. triphcnylumine 400 mg. iodoform mg. p-dimethylaminostyryl pyridine l0 cc. 20' solution of polycarbonate resin in methylene chloride EXAMPLE 2 A second series of film coatings were prepared using the formulation of example 1 to which 50 mg. of 2,5-dimethoxy-4 -aminostilbene were added. The aminostilbene was dissolve in the coating solution prior to preparing the coating.

EXAMPLE 3 The formulation of example 1 was employed with the addition of 0.75 mg. of 4,4 '-methylene'bis-cyclohexylamine.

EXAMPLE 4 Once again the formulation of example 1 was employed. In this example, 3 mg. of 4,4-methylene-bis-cyclohexylamine were added to the formulation and a number of films coated from this mix.

Samples of each of the films prepared in the prior four examples were exposed through a Kodak steptablet to ultraviolet illumination provided by a mercury arc lamp. The total exposure was equal to 100 mj./cm. The radiation from the mercury arc was filtered with a Kimble KG-l heat-absorbing glass filter.

The films were optically developed as described in copending patent application Ser. No. 552,414 filed May 24, l966which issued as U.S. Pat. No. 3,510,300 on May 5, I970. The development was carried out by slowly passing the film under red illumination provided by a 1.5 kw. General Electric Quartzline* lamp. The output from this lamp was filtered wit h a 9 r ni ng 2408 red g lassfilter. The films were optically developed until barely noticeable background fog developed. After development, the films were fixed in an oven at an air temperature of 150 C. for 1 minute. The image density was measured and H and D curves plotted.

Registered trademark of General Electrlc cornpany.

Table 1 compares the results obtained from these four examples.

TABLE I.FILM CHARACTERISTICS Film ol Examle 1 C0 Item trol) Example 2 Example 3 Example 4 Image color Green Sepia-gray Sepia-gray Sepia-gray Exposure required to 10 4 2 1.5

realize net density of 1.0 (mL/cmfl). Gamma 1.8 1.9 2.3 4.0 Base'plus fog density-.. 0.1 0.1 0.1 0.1

It can be seen from this table that both the aminostilbene additive of example 2 and the alicyclic amine additions of examples 3 and 4 serve to increase the sensitivity of the film.

The addition of larger quantities of the alicyclic amine of example 4 has served to increase the gamma or contrast of the material. The addition of the aminostilbene also provides the function of shifting the image color from a green to a neutral, i.e. grey hue.

Both the alicyclic amine and the aminostilbene compounds serve to extend the room temperature film shelf life by a factor of between 2 and 3 compared to the shelf life of otherwise identical film from which the additives were omitted. The presence of either or both additives has an equivalent effect in this regard.

It has been found that either octadecylamine or cyclohexylamine may be substituted for the methylene-bis-cyclohexylamine with equivalent results. Hence it appears that any primary aliphatic or alicyclic amine will be effective in the same way as the methylene-bis-cyclohexylamine. The more volatile aliphatic amines, however, are less efiective over long periods of time due to their loss by volatilization from the film.

The strong inhibiting effect of the primary amine is surprising in view of the fact that secondary or tertiary amines generally more basic than primary amines.

If the p-dimethylaminostyryl pyridine is left out of the formulation in the above examples, the addition of the aminostilbene serves to shift the image color from green to blue.

The inhibiting effects of aliphatic amines may be employed to increase the effective shelf life of these free-radical films. This may be effected by storing the film in a closed container in the presence of a volatile primary aliphatic amine. Upon opening the package and allowing the film to sit in the air for a short period of time, the amine diffuses from the film; thus eliminating the inhibiting effect and allowing the film to function in a normal high speed manner.

The concentration of the 2,5-dimethoxy-4'-aminostilbene in the film formulation is not critical. Effective results are obtained over concentrations varying from 1 part to 50 parts by weight of aminostilbene to 100 parts iodoform.

The concentration of the primary amine is critical as seen from examples 2 and 3. Depending upon the initial concentration of dye salt impurities, amounts of the amine as small as 1 part per 10,000 parts iodoform may be effective. if it is desirable to have an extremely high contrast film, then concentraare ' tions of the amine as high as 2 parts per 100 parts of iodoform may be employed.

The effect of the aminostilbene and the primary amine appear to function independently and no synergism is observed when both the aminostilbene and the primary amine are present in the film; the beneficial results of both compounds being realized.

it is to be understood that other organic halogen compound than iodoform may be used and that mixture of such compounds may be used instead of a single compound. Such compounds are represented by the formula AC-X in which each X is an atom of chlorine, bromine or iodine and A represents a monovalent radical selected from the group consisting of alkyl, aryl, aralkyl, aroyl, hydrogen, chlorine, bromine and iodine (see the compounds listed in US. Pat. No. 3,042,515).

Similarly other equivalents may be substituted for the constituents in the above illustrative examples.

The heating by which fixing is achieved may be at any convenient temperature between about 130 C. and 190 C. for intervals of from about seconds at the higher temperature to about 90 seconds at the lower temperature.

The aminostilbenes to which the present invention is applicable are both the substituted and the unsubstituted orthoor para-aminostilbenes,

instead to the previously described alicyclic primary amines, other aliphatic primary amines may be used to titrate out the dye salt, The more volatile alkyl amines may tend to escape from the film, but if the film is stored in closed containers, the evolved amines then serve as an atmosphere which improves the shelf life of the stored film even if they leave the film prior to exposure.

I claim:

1. In a nonsilver, organic, dry-processed free radical film for recording and duplicating comprising (1) at least one organic halogen containing compound in which at least three halogen atoms are attached to a single carbon atom and which releases free radicals when exposed to a suitable dose of radiation and (2) at least one color forming compound selected from the group consisting of compounds which form a colored reaction product with the free radicals produced from l the improvement which comprises: the incorporation into said composition of at least one organic amine compound selected from the group consisting of (a) aminostilbene compounds, (b) aliphatic primary amines, (c) alicyclic primary amines and (d) mixtures of said compounds, whereby the film speed and shelf life are increased as compared with the film speed and shelf life of similar compositions into which said compound has not been incorporated;" the amount of aminostilbene in said composition being between i to 50 parts by weight for each parts by weight of organic halogen compound and the amount of primary amine in said composition being from 1 to 200 parts of primary amine for each 1,000 parts of organic halogen compound, by weight. 2. A composition according to claim 1 including the compound 2,5-dimethoxy-4-aminostilbene.

3. A composition according to claim 1 including the compound 4,4-methylene-bis-cyclohexylamine.

4. A composition according to claim 1 in which the primary amine is selected from the group consisting of cyclohexylamine, octadecylamine and methylene-bis-c clohexylamine. 5. A composition according to claim 1 inc udlng iodoform as the organic halogen compound and a triphenylmethane compound as the color forming compound.

6. A composition according to claim 5 including a triaryl compound of an element selected from the group consisting of As, Sb, Bi and P.

7. A composition according to claim 5 including an alkyl substituted phenol.

8. A process comprising:

a. preparing a thin film containing the composition of claim b. photographically exposing said composition to a dose of blue or violet radiation to which it is sensitive;

e. optically developing the latent image which results from step (b) by exposing said film uniformly to radiation in the red and infrared; and

d. fixing the resulting visible image by heating the film to about C. for 1 minute.

9. A process for enhancing the shelf life of the film of claim 1 comprising maintaining said film in a vapor consisting essentially of primary alkyl amine while it is stored prior to exposure. 

2. A composition according to claim 1 including the compound 2,5-dimethoxy-4''-aminostilbene.
 3. A composition according to claim 1 including the compound 4, 4''-methylene-bis-cyclohexylamine.
 4. A composition according to claim 1 in which the primary amine is selected from the group consisting of cyclohexylamine, octadecylamine and methylene-bis-cyclohexylamine.
 5. A composition according to claim 1 including iodoform as the organic halogen compound and a triphenylmethane compound as the color forming compound.
 6. A composition according to claim 5 including a triaryl compound of an element selected from the group consisting of As, Sb, Bi and P.
 7. A composition according to claim 5 including an alkyl substituted phenol.
 8. A process comprising: a. preparing a thin film containing the composition of claim 1; b. photographically exposing said composition to a dose of blue or violet radiation to which it is sensitive; c. optically developing the latent image which results from step (b) by exposing said film uniformly to radiation in the red and infrared; and d. fixing the resulting visible image by heating the film to about 150* C. for 1 minute.
 9. A process for enhancing the shelf life of the film of claim 1 comprising maintaining said film in a vapor consisting essentially of primary alkyl amine while it is stored prior to exposure. 